My chicom mechanical switches are quite reliable, omron copies.

They are not too accurate, and the mechanical assys are terrible, in terms of machinist parts.
0.01-02 mm +/- in repeatability/accuracy is terrible.
For my cnc lathe, industrial quality.

But for routers, they are much more than good enough.

(My lathe is for sub-micron or 1 micron repeatability.)

Cheap 5$ optical limit switches provide about 2 microns accuracy, fairly easily.